Speak contemptuously of redesigned title belt, unfinished (8)
I believe the answer is:
belittle
'speak contemptuously of' is the definition.
(to belittle is to dismiss or disparage)
'redesigned title belt unfinished' is the wordplay.
'redesigned' indicates an anagram.
'unfinished' means to remove the last letter.
'title'+'belt'='titlebelt'
'titlebelt' with its last letter taken away is 'titlebel'.
'titlebel' is an anagram of 'BELITTLE'.
(Other definitions for belittle that I've seen before include "Make small" , "Criticise" , "Scoff at" , "Make to seem unimportant" , "Make light of" .)